package 第五周;

public class Circle {
    double radius;
    double area;

    public Circle (double r){
        radius=r;
    }

    public double printArea() {
        area = Math.PI * radius * radius;
        return area;
    }
    public static void main(String[] args) {
        Circle circle=new Circle(5);
        double area=circle.printArea();
        System.out.println(area);
    }
}
